I never used stratification for Selridges, which is pretty close to a Pernetiana. However, as I said, an entire winter full of chills, rains, frosts, decay, expansion, sunrises, and sundowns tend to help a lot.
Also, as Henry has pointed out, sand can help. I dont use sand in my outdoor germination beds, but I do use vermiculite, which has a similar absorption process to silica.
There are two primary issues for the PNW without outdoor germination: squirrels/birds and slugs. This means that the beds require netting and non-toxic slug bait.
While the slugs arenât necessarily a wide spread issue, rodents and birds are. They ADORE rose hips and seeds. LeGrice advised in Rose Growing Complete to make sure any flats maintained over winter outdoors was secured with zinc mesh to prevent mice from devouring the seed. Iâve read they are extremely high in vitamins, even more so than the hip flesh, and we know how popular that is in nutrition supplements. Kim
To ask a further question, is there any pros or cons to keeping the seeds in the hips?
More to the point, I donât want them to sprout before Iâm ready for them. If I leave them in the the hip until a few weeks to a few months before I plant them will this prevent that from happening? I can deal with any rotten hips - I play in dirt for fun. I just had way too many sprout in the fridge last year and want to slow that down.
Iâm thinking about probably taking them out of the hips around January to February with a sow time of March or April. I was getting sprouts last year as early as December and in Iowa thatâs not a good time to get baby roses.
From what Iâve read, written by Harkness and LeGrice, the hips have germination inhibitors in them, preventing germination and possibly delaying it longer after harvest. Iâve read some put the hips in peat and let them rot over winter, but I hate the idea of trying to find them all in that mushy mess. I havenât had any germinate in the baggies if stored without damp toweling and they came up like gangbusters year before last. FWIW. Kim
I like your thinking on that Carle. Can you tell me the novice(looking at breeding) person, your fridge enviroment, temp, the way your seeds were stored(dry, wet paper) or any other relivant info please. I assume the hips, if placed in the fridge, they would be dry ?
Jadae, again as I am new here and some terminology is hard to get the head around could you tell me what âPNWâ stands for, thanks to both in advance, David.
Pacific North West, David. Having put hips in bags in the refrigerator, let me warn you about soggy, mushy, molded goo youâll have to squish through hoping to find the seeds. Not always, but very often in my experience. If that isnât a deterrent, go for it! It is for me. Kim
As posted in previous threads, I received hybrid persica seed from outside Australia (non USA) and decided to store them in the fridge dry in sealed sandwich baggies during our winter. After I guess ~8-9 weeks in this cold stratification, the seed was very dry and showed no signs of molding or other overt disease.
I sowed them I think about 6 weeks ago, in a media consisting of perlite:seedling mix (1:1).
So far, ZERO germinations!!
:0(
Soon after sowing, as luck would have it, the temperatures got a bit too hot, but thankfully in the last few days /week, the weather has cooled right down and there has been a little rain day and night, so I am hoping this might induce some sprouting.
At a guess, the temperature ranges here in the last 6 weeks feel like they have been as follows (I have not researched this to confirm):
60-80F daytime, ~50F night time.
I stick my hips right in the fridge as soon as I harvest them, usually the beginning of October, and they stay there until January, after the holidays, when I have the time to really work with them (and not much else to do in the cold bleak winter months). Occasionally they do get mushy but not that often. I actually like it when they do because itâs easier to get them clean. Those hips are tough! Iâve broken the tip of a knife trying to pry the seeds out of a hip. I just take the mushy ones and rub them against the side of a fine sieve under running water and the seeds come clean quickly and easily. By putting the hips in the fridge right away Iâve found that once I do clean them and stratify them they begin germinating sooner than when I didnât keep them cold for several weeks before hand. Iâve had some germinate in a week or two after stratification. Before it was a good 4 or 5 weeks before anything started to germinate.
I have also used hips that were kept in a freezer for more than a year and when the seeds were stratified had remarkably good germination rates. I was told they wouldnât germinate but my thinking was that Mother Nature keeps them on the frozen ground here all winter and they still seem to germinate so why wouldnât they when kept in my freezer?
And I keep my seeds for 3 years. Surprisingly some germinate better the second year than the first and I still get a few more germinations the third year. I donât think Iâve ever gotten anything to germinate when held longer than that. During their off time over the summer and fall I put the stratified seeds, right in their baggies, in my dark, cool cellar in a plastic bag. Come the next January I clean them again (talk about a gooey, moldy mess) and re-stratify them with my new batch of seeds.
On another note, does any one take them in and out of the fridge? Sometimes if something doesnât seem to be germinating Iâll take them out for a week and put them some place dark but warmer and that will jump start germination. Sometimes theyâre in and out every other week a couple of times before anything happens.
Seil, I do find mushy hips (though stinky) are easy to clean - same way you do, though I also mush them around on dry paper towels which helps separate them.
I also, sometimes take them in and out of the fridge. Not sure Iâve seen it help, but it makes sense if youâre trying to imitate mother nature.
I can confirm that my first hybrid persica germination has occurred this morning from the seed mentioned in my posting ten days ago (see further up)!!!
I am excited about out this!!!
Congratulations, George! I always worry about seeds that dry out, but I guess I shouldnât.
Hi Judith,
Thank you for your kind words!
Your point about drying rose seed is interesting. If memory serves me right, I think Kim Rupert made some mention of a similar technique he has used in stratification, not using wet paper towels, and I tried to copy that technique here. I hope I copied his technique right, LOL!!
I did some embryo work on extremely dried R.gigantea seed early this year, which I had received from India. The seed had extremely low germination rates, and all seedlings were chlorotic and there was 100% mortality. Maybe those very âwaxy-lookingâ embryos were just physically transformed into a more dormant state due to their drying out, which was not conducive to embryo culture. My guess is that if they were given the time and correct conditions some successful germinations might have happened if this seed was not embryo cultured but was instead subjected to more âstandardâ rose seed stratification/sowing. This is all conjecture of course!!
The effect of drying rose seeds on germination rates could make an interesting research topic for someone with the expertise to conduct a good study design.
In this case, I wont know the true germination rates as I plonked the seeds into their little trays without counting numbers. Some trays had like up to 20 seeds others only about 5-10 seeds. Each tray has seed only from the one unique seed parent (xOP).
I think there are 5 little trays in total, and prolly 80 or so seeds altogether in all the trays.
If I even get 2 or 3 more seeds germinate out of the whole lot I will be ecstatic!!!
Thankfully as we approach our mid spring the weather has continued to be mild, unlike the hot spell we got in early spring. I hope this helps matters, I am sure it is not hurting germinations now.
Todayâs forecast is:
minimum 59F , maximum 70F, overcast with occasional showers.
⌠my sorta âbeautiful rose germination dayâ!!
So, lets be clear here. Does it hurt to let the seeds dry for a week or so and then do whatever? It seems more natural to let the seeds dry at least somewhat and, store packaged seeds ARE dry.
David Z did a study on short term drying, with named CVs and found that it was somewhat detrimental. Of course R multiflora is sold dry (fairy rose), and seeds from species are often shipped dry around the world. But it might lower their germination in some cases. My review (RHA home page) on germination discusses the peer-reviewed published literature on this question. Iâve gotten very good germ from R. glutinosa that Tom S sent me last (2009) fall. Whether they store well dried is being tested this winter.
This is an interesting topic. Recently Iâve started letting the seeds dry for a while after I remove them from the hips - not days, but enough hours to let the remainder of the pulp dry out. Since that has been said to be an inhibitor to germination, I felt this would be an easy way to get rid of the remaining tissue rather than hand-knifeclean each seed.
My experience with embryo extraction leads me to think that germinability of seeds is much more affected by the disease state of the embryo and the level of food reserves that it has accumulated than by drying.
Allowing a seed to mature so as to accumulate food reserves is a double-edged sword, though, because it also has time to build higher levels of carotenoids in the testa which are the compounds that fuel abscisic acid production in the stratified seed.
LOL⌠The only one of my hybrid persica to germinate so far also happens to be deformed! It has fused cotyledons on both sides!!! I cut open slits each side to open the two âcotyledonsâ out. After doing that I saw what seems to be a lack of an obvious growth centre inbetween the âcotyledonsâ, just an area of fused tissue.
Hmmmmm⌠maybe this one has real bad genetics.
:0(
Iâd just wait and see what happens.
Too right!!! This one is too precious to throw out even if it is deformed!
One manâs deformity is another manâs beauty. Proliferation sells as do deformed petals. Why not something like this? Take a look at Art Nouveau. Kim
Link: www.helpmefind.com/rose/l.php?l=2.61284